Many implementations of rand() cycle through a short list of numbers, and the low bits have shorter cycles. The way that some programs call rand() is awful, and calculating a good seed to pass to srand() is hard. The best way to generate random numbers in C is to use a third-party library like OpenSSL.

Context Explanation

For example, M + rand() / (RAND_MAX / (N - M + 1) + 1) (Note, by the way, that RAND_MAX is a constant telling you what the fixed range of the C library rand function is. You cannot set RAND_MAX to some other value, and there is no way of requesting that rand return numbers in some other range.) If you're starting with a random number generator which returns floating-point values between 0 and 1 (such as ... How do I get a specific range of numbers from rand ()? The rand() function returns a pseudo-random integer in the range 0 to RAND_MAX inclusive (i.e., the mathematical range [0, RAND_MAX]).

Insight Material

The srand() function sets its argument as the seed for a new sequence of pseudo-random integers to be returned by rand(). These sequences are repeatable by calling srand() with the same seed value. The actual implementation of the random number generator is left unspecified, so the actual behavior is specific to the implementation. The important thing to remember is that rand does not return random numbers; it returns pseudo-random numbers, and the values it returns are determined by the seed value and the number of times rand has been ... How does rand() work?

Final Conclusion

Does it have certain tendencies? Is there ... A second lesson is that this shows another way in which <random> is easier to use than rand() and manually computing your own distributions. The built-in uniform_int_distribution allows you to directly state the desired, inclusive range. c++ - How does modulus and rand () work? - Stack Overflow